The paper's authors say these views are obstructing efforts to prevent the spread of HIV among African-Americans, the racial group most likely to contract the virus.
"The findings are striking, and a wake-up call to the prevention community," Laura Bogart, a behavioural scientist who co-authored the study, told the Washington Post.
"The prevention community has not addressed conspiracy beliefs in the context of prevention. I think that a lot of people involved in prevention may not be from the community where they are trying to prevent HIV."
African-Americans are 13% of the US population but account for 50% of new HIV infections, according to the Centres for Disease Control and Prevention.
African-American women constituted 73% of new female HIV cases in 2003.
The study, which was supported by the National Institute of Child Health and Human Development, also revealed a slight majority believe a cure for Aids is being withheld from the poor; 44% think the people who take the new medicines for HIV are being used as government guinea pigs, and 15% believe Aids is a form of genocide against black people. The responses barely fluctuated according to age, income, gender or education level.
Na'im Akbar, a professor of psychology at Florida State University who specialises in African-American behaviour, stressed that these views are grounded in experience.
Between 1932 and 1972 the federal government conducted experiments on 400 African-Americans in Tuskegee, Alabama. They were told they were being treated for syphilis but were allowed to sicken and die, and in some cases were actively denied treatment, until the experiment was exposed in 1972.
"This is not a bunch of crazy people running around saying they're out to get us," he said.
However, others, including Phil Wilson, executive director of the Black Aids Institute, insist that African-Americans must come to terms with this past if they are to overcome belief in conspiracy theories and the obstacles they present to effective prevention.
"The syphilis study was real, but it happened 40 years ago, and holding on to it is killing us," he said.